Right Thinking from the Left Coast

Tag: high-energy neutrons

From the other side of a wide glass window on the third story of the National Ignition Facility (NIF), the world’s largest laser array looks an awful lot like the world’s largest plumbing project. Row after row of 16-inch-diameter pipes are packed into a room like cigarettes in a box—only the box is the size of three football fields. A catwalk thick with miles of cable runs through the center. Large metal ducts snake overhead and along the walls. I have to take it on faith that the pipes, called beam tubes, don’t contain water or gas, but 192 separate laser beams zipping back and forth. When the beams finally exit the room, their strength amplified more than a quadrillion times, they will converge on a pencil-eraser-size target in one short, powerful pulse. And in those 20-billionths of a second, I’m told, atoms of hydrogen will smash together with such force that they’ll essentially create a star.

It sounds impressive—and certainly looks imposing—but society has been taking promises of fusion on faith for more than five decades. If fusion works as proponents claim, it could produce enough clean energy to power the world for hundreds and hundreds of years to come. One of the first hurdles is the tiniest component, the fuel: Hydrogen isotopes, such as deuterium and tritium, adamantly resist uniting, regardless of the amount of heat and steel and funding thrown into the effort.

But this past fall, physicists at NIF, based at Lawrence Livermore National Laboratory in California, made an important advance with their elaborate building and enormous laser: They fired 121 kilojoules of ultraviolet light into the $3.5 billion facility’s target chamber, causing deuterium and tritium nuclei to fuse into helium atoms, releasing 300 trillion high-energy neutrons. Even though NIF and other labs have created fusion before, the achievement brings researchers a step closer to conquering the ultimate challenge: a fusion reaction that produces more energy than is required to start it.

Expensive megaprograms such as NIF aren’t the only ventures making progress. At the other end of the funding spectrum, a number of innovative startups have also begun to yield promising results. After decades of frustratingly slow research, the emergence of real, practical fusion power may come down to a race between these entrepreneurial Davids and the government-run Goliaths.

Hope this pans out, because we need that energy and will need a lot more of it as more people start enjoying the wonders of a modern society, because just like those that point out teaching abstinence doesn’t work too well, the advice of some crazy guy about how people should just not reproduce isn’t the answer. Now if I could just figure out how much energy those 300 trillion high-energy neutrons really equate to…..